Highlighted text can be produced on printed text, in a journal or a textbook. Highlighted text is also produced in electronic documents, using common word processing editors or pdf viewers. Typically, a reader marks text using highlighting means in order to display the text in a way that stands out on a paper or on a computer screen. One may add an annotation to the highlighted text to insert extra information related with the marked text. Also, an annotation can be inserted at a particular point in a document without marking the text at or near the annotation insertion point.